Band track



R. w. SMITH BAND TRACK May 13, 1952 Filed March 23, 1948 Jib Z JUL/E732 Patented May 13, 1952 UNITED 2,599,919 OFFICE BAND TRACK Robert W. Smith, Copley, Ohio, assignor to The B. F. Goodrich Company, New York, N. Y., a

corporation of New York Application March 23, 1948, Serial No. 16,539

8 Claims. (01. 305-) This invention relates to band tracks for selflaying track-type vehicles and is especially useful for farm tractors although the invention is also useful onmilitary and other vehicles.

Tracks proposed heretofore for resisting bending in one direction and thereby reducing the number of bogie wheels by supporting the vehicleupon the reach of track between relatively widely spaced guide wheels have had the disadvantage of being formed of metallic blocks or linkshinged to each other by pins in transverse openings in the links or blocks, and it has been found that due to the fact that high shear stresses were present at the hinge pins and also excessively high bearing pressures, lubrication of the pins has been difficult and rapid wear of the pins has objectionably lessened or destroyed the bridging ability of the track. The wear of the hinging parts has resulted in objectionable lengthening of the track and separation of the par s.

'It is an object of the present invention to overcome the foregoing and other difliculties.

Other objects are to provide a track in which no hinge pins are required, to provide a flexible band track having truss-like resistance to bending in one direction, to provide for maintaining this truss action effectively despite ordinary wear of'track' parts, to provide for convenient replacement of worn or defective parts, and to pro-' vide effective cushioning of the track against shock forces.

These and other objects wil1 appear from the following description and the accompanying drawings.

Of the drawings,

Fig. 1 is a, plan view of a portion of the track showing the wheel-contacting face thereof.

Fig. 2 is a side elevation thereof, partly in section taken on line 22 of Fig. 1.

Fig. 3 is a cross-sectional view thereof taken on line 3 3 of Fig. 1.

Fig. vl is a side elevation of the track on the vehicle.

Referring to the drawings which show a track constructed in accordance with and embodying the invention, the numerals l0, H designate flexible bands, which may be endless, of soft vulcanized rubber or other rubber-like material eachhaving a layer of flexible tension elements l2 embedded therein in spaced-apart relation and'bonded thereto. preferably of wire cable and completely surrounded by rubber-like material to protect them from moisture and to cushion them from each other and from the bogie wheels I3, l4 and other parts of the track.

Embedded in the bands 10, -H at equally The tension elements are' spaced apart intervals therealong, are metal straps I5 having ears [6 extending therefrom toward the center of thetrack and ears ll exteriding'i-outwardly toward'the'm'argin s of the tracl 'z i The straps f5" r nay also havet'eibs l5a bent away from the strap toward the cables at the sides thereof for laterally confining the cables. Shoes, each comprising a metal plate l8. and a rubber tread l9 bonded thereto at one face thereof, are provided at spaced-apart intervals longitudinally of the track, and extend cross-wise thereof. 7

Each shoe is attached to the pair of bands H], II by means of bolts 20 which clamp the ears [6, H to the plate l8, spacers 2| being provided about the bolts between the plate I8 and the ears l6, H to prevent undesirable compression of the rubber-like material of the bands. The straps l5 are located above the tension members 12 so that these and the rubber-like material which surrounds them are confined between the straps l5 and the plate l8 with the rubber-like material surrounding them under slight compression sufiicient to hold the shoes in the desired spacing while at the same time the tension elements are each cushioned by surrounding rubber-like material. The cables l2 and the metal'straps are connected to the rubber-like material by a vulcanized bond for transmission of driving forces between them without undue relative movement.

For strengthening the track against side-wise deflection, and for driving the track, each plate l8 has a clearance opening 30 at its center for receiving a tooth of a drive sprocket 3|, and a wear plate 32 having a corresponding opening 33 in alignment therewith, is secured to each plate 18 by bolts 34. Each wear plate 32 has a pair of upstanding guide flanges 35, 36 flanking the opening 33. The guide flanges have sprocketflanking portions 35a, 36a and. laterally offset portions 35b, 36b to provide sliding engagement with the portions 35a, 36a of adjoining flanges which they overlap and thereby steady the track in use against undesirable sidewise deflection. The offset portions of flanges 35, 36 are of opposite hand.

For providing resistance against reentrant bending of the track, the flange portions 35a, 36a are provided with laterally projecting lugs 40, 4| extending toward the side margins of the track and the flange portions 35?), 36b are provided with lugs 42, 43 adapted to engage lugs 40, 4| at a position where the tread face of the track is slightly convex longitudinally, as shown in Fig. 4, and the wear plates are made of such span as to contact each other successively, as at 44, with edge faces rounded toward the Wheel-contacting face of the track to provide rolling engagement with each other-when the wheel contacting face is bowed in a convex manner to pass about the wheels. As the lugs 40, 4|, 42, 43 are well spaced from the tension'members of the track, they carry the tension component of the bending stress of the track while the compression component is carried by the contacting wear plates, leaving the cable tension members to carry the driving forces. The end faces'of the wearplates 32 haveinterlocking, notches 32cc. and the, lugs; 32 b. toi pro;- vide against lateral shifting relative to each other. Also the abutting faces of the wear plates? are arranged so that a flange 36a of one overhangs the base of the adjoining wear plate as at 60 causing the wear plates torbeinterlockedvertically and preventing shifting. under shear. stresses.

The lugs 40, 4|, 42, 43 preferably have fiat contacting faces providing a broad area' for-'reduc'--- ing unit stress and abrasive wear. As the wear plates and their flangesiare bolted to the plates I8 theymay. be-individuallyremovedand replaced. incase. of: Wear orbreakage.

For strengthening, the shoes andfstifieningthe treads. thereot,. bars 45'; of angular, cross section may. be embeddeiin. the. rubber-like. material of the. treadsextending cross-wisezof; theitrack' and secured to the plates I Bby therbolt's'fl'which secure. the. wear plates.

The construction-issuchvthat by virtue, of the flexible. tension-resistingelements.extendinglone gitudinally. otthe trachcontinuouslyirom truss memberto. t'russmember. and .securedto. the'truss members-the trussmemb'ers are. flexibly'hingedito each. other, and the. use of hinge pins. subject to. rapidlwear, due to high unittbearingpressure; isavoided; whileat. thesame time therubber-l'ike material about; the tension. elements cushions themagainstl sudden application. 01E;- shock" loads; The. contactv of the Wear. plates in abutting; en"- gagement. with. each other. holds, them at the proper. spacing whiletheinot'ches andilugs thereon..toge.ther.With.the.overhang of the wear plat'es interlocks them; against laterah shiftingand thin overlapping, flangesprevent. side. sway, of. the track. Also the provision of.'the/tension elements in groups enclosed: by. the. rubberrlilie. material facilitates. manufacture. and replacement; of parts.

Variations. may. bexmadeflwithont departing, fromthe scopeofltheinvention as, it'is. definediby the following claims.

L Abandrtracli for disposition. aboutv fore, and. aft. spaced; Wheels. of a. self.-lay-ihg tracketyp'e.

vehicle to provide a. ground-contacting reach. off the. track. free. of! b'ogierwheel. contact. between the wheels for'supporting the vehicle. from the. ground,,said-tracknomprising a snbstantiallyine extensible flexible band-extending longitudinally ofthe. track" and having a surfacesfor directly.-

engaging said wheels, said band having. flexible. tension-resisting elements? for resisting. stretch of? the i band, a.- .ser.ies ofi, plates. secured. totand; mounted-upon .saidbandrin iabutting contact.- one 7 with: another ini succession at the plane; of the; tensi'oneresisting elements:torsustain longitudinal. compression. loads on the. track, guidee flanges upstanding from said plates at-ithe-dnner face-of. the track. for guiding; engagement with: said.

wheels; saidguideiflanges-a having portions over lapping. each-other 'inrsuccession toprevent sidesway of: the? track. in: thereach-v between; the wheels;v and: laterally. extending; lugs: on? said piatesrfor-limitingi. upward bowing of" said: track at; said; groundecontactinga reachiby abutting en gagement: of: lugs" onsuccessive; guide; flangesthroughouttsaid reachito :provide: a. trussed reach of the a track: from wheel 1 tn: wheel, .said tracking.

being: bendable: in: the opposite direction" with:

separation of saidi lugs -to' permit" travelioff the track A about saidwheels.

2. A band track for disposition aboutiioraand;

aft spaeed: Wheels. of a. self-laying track-type vehicle; to; provide: a ground'contacting; reach of the track free of bogie-wheel contact between the wheels for supporting the vehicle from the ground, said track'comprising a pair of substanmany inextensible flexible bands extending 1ongitudinallg ofthe. track in spaced-apart relation and havingia. surface for directly engaging said wheels-,saidibandsseach having flexible tensionresisting elements embedded therein for resisting-stretch of the-band, a series of plates secured toandsmounted upon said bands in abutting contact one with another in succession at the plane ofithe tension-resisting; elements to sustain longitudinal; compression loads on the track, L guide. flangesupstanding from'said'plates atth'efinner' face of" the" track for; guiding: engagementiwith said wheel's, said guide' flanges h'aving' portions overlapping; each" other: in succession to prevent. sidesway' of the" track in the reach between. the? wheels, and laterally" extending: lugs; on.v said: plates" for. limiting. upward bowing .of said track. at said ground conta'cting reaich;by" abutting; engagement. of." lugs on successive guide? flanges throughout'saidreachtoprovide a'ttrusseld'lreach' of the trackfrom wlieelto'wheelisaid t'racli being. freely bendable. inithe. opnosite' direction with. separation of; said lugs to permit'stravelf oflthe, track. about" said. wheels.

3. Aband traclior. disposition.abnut ibre-andi aft; spaced; wheels of a. sel'f laying; track-type? vehicleto provide aground-contacting, reachofl the. trackiree oibogie=wheellcontact 'betweemtha wheels for supporting the vehicle from. the. ground-,, said I track comprising a. pair. of. substantially, inextensible.flexibleibandsrextending, Ion,- gitudinallyi of. the track. inspacedrapart relation and'l having .a surface for: directly, engaging: said, wheels,.said.bands. each having flexible tensionw resisting elements; for resisting; stretohofl thef 581K159 ser-iesof: platesssecuredr to:- and; mounted; upon. said. bands in: abutting contact. ones with another in succession. at; the planeof? the; tern,

s-ioneresist-ing elementsto sustainlongitudinal;

compression loads on the track, saidiplates hawing; rounded. edgesrfor. rolling,v engagement. one

with another, guiderfianges upstanding fromrsaidi plates between said bands at the inner faoerofi the track for guiding engagement withi said Wheelsasaid guide-flanges having: portions overlapping; each-:other in! succession. to prevent-side sway of. the track-l. in the.' reach between the wheels, and laterally extending; lugs our saidss plates for limiting: upwardabow-ing; of said: track at said ground-contacting reach. bwabuttingmnw gagement. of: lugs" on; successive": guide: flanges throughout said reach to provide a trussedimaciir of :the: track :frommheel: to -wheeL-said traclezbein freely benda'b1e1 in; the: opposite; direction: with: separation of said lugs torpermit travelaofithe; trackv about said? wheels.

41: Aband trackifor: disposition aboutr forezan'd: ait spaced wheelse of: at self'w-laying' track f'typwvehicle-:to provide: a groundecontactingi reach of the; traclet free of: boziewheel; contact: betweeni thmwhee-lsifor: supporting thesvehicle-t from: the-1. ground; said:tracliqcomprisingraspain"offsubsteme tiaily inex-tensible flexible: bands: extending: Iona gitudinally of the track and"havihgraisurfacezfoni directly engaging said wheels, said.bandshaving.- flexible? tension-resisting: elements? for: resisting stretch of the. bands; a seri'es'ot plates securedito? and 'mount'ed: upon said. bands i'n xabutti'ng co 4 tact one. with. another:irnsuccessionsat tth'eeplane oft;thestensioneresistingrreiementsetmsustainlozrajgimdinai. compression; meme; theetraek: saith? plates having rounded edges for rolling engagement one with another, ground-engaging shoes secured to said plates, guide flanges upstanding from said plates at the inner face of the track for guiding engagement with said wheels, said guide flanges having portions overlapping each other in succession for sliding engagement to prevent sidesway of the track in the reach between the wheels, and laterally extending lugs on said plates for limiting upward bowing of said track at said ground-contacting reach by abutting engagement of lugs on successive guide flanges throughout said reach to provide a trussed reach of the track from wheel to wheel, said track being freely bendable in the opposite direction with separation of said lugs topermit travel of the track about said wheels.

5. A band track for disposition about fore and aft spaced wheels of a self-laying track-type vehicle to provide a ground-contacting reach of the track free of bogie-wheel contact between the wheels for supporting the vehicle from the ground, said track comprising a substantially inextensible flexible band extending longitudinally of the track and having a surface for directly engaging said wheels, said band having flexible tension-resisting elements for resisting stretch of the band, a series of plates secured to and mounted upon said band in abutting contact one with another in succession at the plane of the tension-resisting elements to sustain longitudinal compression loads on the track, flanges fixed to and upstanding from said plates at the inner face of the track and comprising stop surfaces on said plates for limiting upward bowing of said track at said ground-contacting reach by abutting engagement'of said stop surfaces on successive flanges throughout said reach to provide a trussed reach of the track from wheel to wheel, said track being bendable in the opposite direction with separation of said stop surfaces to permit travel of the track about said wheels.

6. A band track for disposition about fore and aft spaced wheels of a self-laying track-type vehicle to provide a ground-contacting reach of the track free of bogie-wheel contact between the wheels for supporting the vehicle from the ground, said track comprising a substantially inextensible flexible band extending longitudinally of the track and having a surface for directly engaging said wheels, said band having flexible tension-resisting elements for resisting stretch of the band, a series of plates secured to and mounted upon said band in abutting contact one with another in succession at the plane of the tension-resisting elements to sustain longitudinal compression loads on the track, flanges upstand ing from said plates'at the inside face of the track, said flanges having portions overlapping one another in sliding engagement for limiting sidesway of the track and stop surfaces for limiting upward bowing of the track at said groundcontacting reach by abutting engagement of said stop surfaces on successive flanges throughout said reach to provide a trussed reach of the track from wheel to wheel, said track being bendable in the opposite direction with separation of said stop surfaces to permit travel of the track about said wheels.

7. A band track for disposition about fore and aft spaced wheels of a self-laying track-type vehicle to provide a ground-contacting reach of the track free of bogie-wheel contact between the wheels for supporting the vehicle from the ground, said track comprising a substantially inextensible flexible band extending longitudinally of the track and having a surface for directly engaging said wheels, said band having flexible tension-resisting elements for resisting stretch of the band, a series of plates secured to and mounted upon said band in contact one with another in succession at the plane of the tension resisting elements to sustain longitudinal compression loads on the track, said plates having rounded meeting surfaces in rolling engagement one with another, flanges upstanding from said plates at the inside face of the track, said flanges having portions overlapping one another in sliding engagement for limiting sidesway of the track in the reach between the wheels and stop surfaces for limiting upward bowing of the track at said ground-contacting reach by abutting engagement of said stop surfaces on successive flanges throughout said reach to provide a trussed reach of the track from wheel to wheel, said track being bendable in the opposite direction with separation of said stop surfaces to permit travel of the track about said wheels.

8. A band track for disposition about fore and aft spaced wheels of a self-laying track type vehicle to provide a ground-contacting reach of the track free of bogie-wheel contact between the wheels for supporting the vehicle from the ground, said track comprising a substantially inextensible flexible band extending longitudinally of the track and having a surface for directly engaging said wheels, said band having flexible tension-resisting elements for resisting stretch of the band, a series of plates secured to and mounted upon said band in contact one with another in succession at the plane of the tensionresisting elements to sustain longitudinal compression loads on the track, flanges upstanding from said plates at the inner face of the track, said flanges each extending longitudinally of the track and having portions in alignment with one another and portions laterally offset therefrom to engage the succeeding flange in sliding overlapping engagement therewith for limiting sidesway of the track, laterally projecting lugs on said offset portions having stop surfaces for engaging lugs on the succeeding adjacent flange for limiting upward bowing of the track at said ground-contacting reach by abutting engagement of said stop surfaces on successive flanges throughout said reach to provide a trussed reach of the track from wheel to wheel, said track being bendable in the opposite direction with separation of said stop surfaces to permit travel of the track about said wheels.

ROBERT W. SMITH.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,786,539 Kegresse Dec. 30, 1930 2,107,490 Mayne Feb. 8, 1938 2,329,582 Bishop Sept. 14, 1943 2,362,638 Kilborn Nov. 14, 1944 2,392,988 Keck Jan. 15, 1946 2,420,133 Hardig May 6, 1947 FOREIGN PATENTS Number Country Date 544,856 France July 5, 1922 49,771 France Apr. 4, 1939 (Addition) 

